Gear cutter



@EL 2l 1924. 1,512,543

F W. JURY GEAR CUTTER Files Nov. 9, 1922 graffg/ w Gf@ Patented oa. 21.1924.

PATENT OFFICE.

AII'BASNK W. JUBY, 0F MILWAUKEE, WISCONSIN.

am CUTTER.

application mea november s, 1922. smal No. 599,799.

To all whom z't may concern.' I

Be it known that I, FRANK W. Jim1', a subject of Great Britain, and resident of Milwaukee, in the county of Milwaukee. and State of Wisconsin, have invented certain new land useful Improvements in Gear Cutters; and I do hereby declare that the followin is a full, clear, and exact description t ereof.

This invention relates to cutters for use in orming spur ears, spiral and double helical or herringne gears.

Objects of this invention are to provide cutters which may be used in machines of the type disclosed in Patent No. 1,456,240

issued to me May 22, 1923, for gear cuttin machine or in fact, to provide ,cutters whic may be used with any typen of gear cutting mach'ines in which the cutters are slantingly reciprocated and advance along a linev around the blank and gradually finish them u to the exact contour desired in one opera-y tion or cycle of the machine.

lFurther objects are to provide cutters which may be easily fproduced, which are of strong and rugged ormation, and which are so constructed as to have long life. f An embodiment of the invention is shown in the accompanying drawings, in which Figure 1 is a face view of a cutter showing its relative position to a gear blank, such blank being indicated in dotted lines.

Figure 2 is a view looking directly at the teeth of the cutter from the front and showing in dotted lines the face of the gear blank with the cutter at its central position with reference to the blank 'and in dotted lines showing the second cutter in the posiltion it assumes at this instant.

downwardly tangentially and at the same v lines in Figure 2. Atl machine of this gen eral typeis disclosed in my co-pending application identified above.

The cutters are duplicates except that one is a right hand cutter and the other a left hand cutter, and it will, therefore, be necessary to describe in detail only onecutter.

The ,cutterocomprises a body ortion 1 which is substantially rectangular 1n formation from which project a plurality of teeth 2. Theseteeth are the cutting teeth of the tool and are arranged slantingly to the front face 3 ofthe cutter corredponding to the angle of the teeth, as indicated in dotted lines at 4 in Figure 2. In the drawings this cutter is illustra-ted as movin tangentially in a downwardly vertical ine with reference to the gear blank. It is understood, of course, that the cutter ma movel along any tangential line desired, ut for convenience it will be recited in detail, as shown in the drawings, that is to say, as moving along a vertical tangential line with reference to the gear blank.

The lowest of the cutting teeth Z'are relatively short and are` progressively longer as the upper portion of the cutter is approached, the uppermost teeth having the cutting edges of their tops lyin in a line substantially parallel to the line joining the faces of the teeth. This upper face 6 of the teeth slopes backwardly away from the cutting face 3, as may be clearlyseen from Figure 3.

By referring to Figures 1 and 2, it will be .seen that the face 7 of the teeth joins the face 3 of the cutter at an acute angle and therefore provides an acute cutting side edge for the teeth. The plane of the other side 8 of. the teeth joins the face 3 at an obtuse angle. In orderv to provide an acute cutting edge for this corner of the cutting teeth a kerf 9 is cut out of the Aface of the tooth, as is most clearly shown in Figuresl and 3. It is to be noted that this kerf joins the plane 8 at the lie where such lane intersects the plane of the face 3 o the cutter. It is, also, to be noted that the outer end'of this kerf dies away before it reaches the extreme top cutting edge or corner of the is also a straight line. It is also to be, noted that all of these lines lie in the sameiplane, that is to say, in the pla'ne of the face 3 of thevcutter. a

With a cutter of this type it is possible to utilize a machine which reciprocates the cutter to the exact central plane 11 (see Figure 2) of the' gear blank without marring the apex of the teeth. It is also possible to alternately reciprocate cutters first from one side and then from theother side of the gear blank, stopping each cutter at'the exact center line, the cutters occupying 'the relative positions, as indicated in full and dotted lines in Figure 2.

As will be' more fully 'understood from reference to my previously identified application, these cutters are adapted to be reciprocated along slanting lines while the gear blank slowly rotates upwardly' past the cutter. At the same time the cutters are slowly fed downwardly, the teeth are gradually increasing inlength, permitting this direct downwardly tangenti-al feed. It is to be noted that the gear blank executes several complete rotations before the uppermost or nishing teeth of the cutter are brought into action. In this manner the teeth are partially formed completely around the gear Without finishing any one tooth before theother teeth are cut out. It will, therefore, be seen that cutters constructed, as outlined in this application, are particularly adapted for this manner of forming gears and will, therefore, produce gears which are not warped, due to sudden relief of internal strain at any one point, but will produce gears in which thel exact contour of each tooth in the gear is maintained throughout the entire extent of the gear.

It may be further pointed out that from actual practice it has been found that completely lfinishing one tooth at a time in a fr gear blank produces a warpin effect upon the blank, g

due, as pointed out above, to the j relief at one point only of the internal stresses so that the gear blank changes its contour. when it is remembered that lone'tooth alone is completely nished before the next tooth is started, it becomes apparent that the `Wear upon the cutting tool, before such cutting tool arrives at the last tooth, is enormous. For this reason, it 1s apparent that the last tooth will not have the same contour as the first tooth. From actual tests conducted with gear cutting machmes which completely form one tooth at a time, it has been found that the nal teeth are different in contour from therst of cutting teeth of gradual y 'of the extent of said cutter, and

and to gradually finish these cut gears completely around the blank, thereby avoiding any dierence in contour or any warping ot the gear blank.

I claim 1. A gear cutter comprisin a plurality increasin height, with the cutting edges of all of said teeth lying in the same plane.

2. A gear cutter 'comprising a plurality of slanting cutting teeth having acute cutting edges on both sides and at their top, all of such cutting edges lying substantially in one plane.

3. A gear cutter for ashioning herringbone gears comprising a plurality of cutting teeth 'all of Whose cutting edges lie in the same plane.

4. A gear cutter comprising a body portion having a plurality of outwardly projecting cutting teeth each of which 1s provided with `a slanting top and an' larly arranged sides, 'one of said sides xiving an edge formed by an undercut lip.

5. A gear cutter for fashioning herringbone gears comprising a body portion having a plurality of outwardly projecting cutting teethwith the cutting ed s of all of the teeth lying in substantial y the same plane having their bases lying in a straight line and their tops lying in a llne at an angle to said first mentioned line for a ortion aving their tops lying in a line substantially aral- `lel to said first mentioned line for t e redouble helical gears comprising a body portion having a plurality of outwardl rojecting teeth arranged at an angle wit i t eir tops slanting downwardly towards the body om the top cutting edge, each tooth having an acute cutting edge on one side formed by the planes of the side and face of thetooth and having a kerf cut into its face to provide an acute cutting edge at the other side of the tooth. l

7. A cutter for fashioning the teeth of helical gears comprising a body portion having a plurality of outwardly rejecting teeth arranged at an angle with a l of their cutting edges arranged 1n substantially the same plane, the thickness ofcorresponding portions of certain of the teeth gradually decreasing as one end of the cutter is approached.

,8; A cutter for' fashionng the teeth of double helical gears comprising s, body portionhaving a pluralit of outwardly pro.- the other side of the tooth, the height of jecting )seeth arranged, at an angle with certain of said teeth aduallydecreasing l0 their tops slanting downwardly towards the towards one end of sai cutter.. body from the top cutting edge, each tooth -In testimony that I claim the foregoing 5 having" an acute cutting edge on one side I have hereunto set my hand Aat Milwaukee, formed by the lanes of the side and face in the county of'Milwaukee and State of of the tooth an having a kerfcut into its Wisconsin. face to provide van 'acute cutting edge at FRANK W. JURY. 

